Au nanoparticles and reduced graphene oxide based plasmonic photodetector with enhanced performance in visible spectral region

This work reports on a photodetector (PD) based on SiO2 substrate, Au nanoparticles (NPs) and reduced graphene oxide (rGO) thin layer with plasmonic enhancement of light absorption in visible spectral region. Finite difference time domain (FDTD) methodology is used for simulation. The results show that a surrounding medium with higher refractive index (RI) leads to greater absorption with plasmonic enhancement resulting in higher magnitudes of quantum efficiency (eta) and responsivity (rho). The proposed PD design operating at 654.52 nm provides the values of eta and rho as large as 0.527 and 0.278 A/W, respectively. Further, a possible practical implementation of the proposed PD design is reported while analyzing it with Au electrodes and rGO acting as a conducting layer. This analysis comprises of dark current (Idark) estimation followed by the evaluation of detectivity (D) and detectable power (Pd). SiO2-rGO (6 nm)-Au NPs (6 nm radius) structure (with surrounding medium RI = 1.33) further achieves the values of Idark, D, and Pd as 6.33 x 10-14 A, 1.36 x 1011 Jones, and 2.28 x 10-13 W, respectively. Further, the proposed PD design is able to provide superior performance (i.e., small Idark along with large values of D and rho) compared to recently-reported (2020-23) PD designs in visible range.